(function(){
    var designW = 750;  //设计稿宽
    var font_rate = 100;
    //适配
document.getElementsByTagName("html")[0].style.fontSize = (document.body || document.documentElement).offsetWidth / designW * font_rate + "px";
document.getElementsByTagName("body")[0].style.fontSize = (document.body || document.documentElement).offsetWidth / designW * font_rate + "px";

    //监测窗口大小变化
    window.addEventListener("onorientationchange" in window ? "orientationchange" : "resize", function() {
            setTimeout(function(){
                    document.getElementsByTagName("html")[0].style.fontSize = (document.body || document.documentElement).offsetWidth / designW * font_rate + "px";
                    document.getElementsByTagName("body")[0].style.fontSize = (document.body || document.documentElement).offsetWidth / designW * font_rate + "px";
                             
            },200)
 }, false);
        })();